The existence of a living will, medical power of attorney, durable power of attorney or other advance directive, duly executed by a person alleged to be a “protected person”, as defined in section four of this article, or the prior appointment of a surrogate decisionmaker for the protected person may eliminate, limit or supersede the need for the assistance or protection of a guardian or conservator, and any person so appointed is to be the first preferred nominee for guardian or conservator, as set forth in section eight, article two of this chapter.